1. Field of the Invention
This invention is generally directed to automatic circuits for providing automatic daytime running lights (DRL) for automotive vehicles and, more particularly, to a double relay switch system for providing DRL whenever a vehicle ignition switch is ON and a starter switch is OFF and dependent upon the condition of manual overrides, ambient condition sensors and vehicle condition sensors.
2. History of the Related Art
Automatic headlight and daytime running light (DRL) systems are known for use with automotive vehicles. Such systems are designed to provide illumination of vehicle headlights and, in some cases, parking or taillights and ICC trailer running lights for purposes of improving the manner in which a vehicle is made conspicuous in the daytime to thereby increase safety. Some existing systems provide for energizing the high beam filaments of the vehicle headlights at reduced power and others energize the lowbeam filaments of the headlights at normal power.
In addition to the foregoing, other systems have been designed for further controlling the operation of a vehicle exterior lighting system depending upon ambient conditions, such as ambient light levels and moisture conditions, to ensure that a vehicle's headlights, parking or taillights and running lights are fully illuminated in the event ambient conditions warrant such illumination during daylight hours.
Also, to reduce the drain on a vehicle battery, other systems have been designed for controlling the illumination of a vehicle exterior lighting system depending upon the condition of the vehicle's ignition and starter switches. In most such systems, the vehicle circuit includes a manual switch for activating the vehicle exterior lighting system with such protective circuits only being activated or useful in the event the manual switch is in the ON condition.
Some examples of prior art daytime running light systems are disclosed in U.S. Pat. Nos. 4,684,819 to Haag et al., 4,899,083 to Kataoka, 4,686,423 to Eydt, 4,831,310 to Heintzberger et al., and 4,667,129 to Papillons et al. Systems for preventing a drain on a battery system during starting are disclosed in U.S. Pat. Nos. 3,764,816 to Johnson, 2,449,338 to Summersett, 3,993,914 to Conrad et al., 3,348,095 to Gold, 3,385,998 to Gold, 3,430,100 to Dill, 3,414,763 to Kibler and 4,862,036 to Kriss.
Systems which are associated with daylight running light systems and which incorporate ambient condition light control circuits are disclosed in U.S. Pat. No. 4,956,562, 5,136,209, 5,185,558 and 5,614,788, all of which are assigned to the same Assignee as the present application.